1. Field of the Invention
The invention relates to transport cases with hinged side parts made of plastic, whose side parts are subject to special technical demands. The side parts have either a board height that is greater than 16 centimeters or they must reliably withstand loads greater than 16 kg. In addition, the hinged side parts are provided with wicket-shaped hollow stiffening strips. Such cases are used for logistical purposes. The cases are generally stackable and many different types of unit items can be transported in them.
2. Description of the Related Art
In contrast to rigid cases, when the side parts are hinged the problem is more likely to occur that one individual side part is not sufficiently torsionally rigid. This basic problem intensifies as the board height of the side parts increases and as the weight′ of the load increases. Because as the surface area required for the side parts increases and as the load pressure increases, the strength of the plastic is no longer adequate to guarantee sufficient torsional rigidity. One skilled in the art uses stiffening strips to counter this problem. Known in particular from the prior art in accordance with EP 0 396 728 B2 (FIG. 7) are wicket-shaped hollow stiffening strips. The invention starts from this prior art.
In contrast to rigid cases, when the side parts are hinged the problem is more likely to occur that one individual side part is not sufficiently torsionally rigid. This basic problem intensifies as the board height of the side parts increases and as the weight′ of the load increases. Because as the surface area required for the side parts increases and as the load pressure increases, the strength of the plastic is no longer adequate to guarantee sufficient torsional rigidity. One skilled in the art uses stiffening strips to counter this problem. Known in particular from the prior art in accordance with EP 0 396 728 B2 (FIG. 7) are wicket-shaped hollow stiffening strips. The invention starts from this prior art.
In terms of the technical starting point for the invention, however, another problem remains unresolved that has to do with the fact that the known hollow U-leg is produced by injecting gas. The pressure and flow conditions that can be produced by injecting gas are not adequate for producing a truly smooth external skin of the hollow stiffening channels. This means the hygiene and carrying comfort of the transport cases is negatively affected in particular when the upper edge of the wicket-shaped reinforcing strip is used simultaneously as a handle.